People descended from apelike predecessors through a long process of transformation known as human evolution. We know that a variety of creatures have inhabited the Earth before, and even alongside modern human beings. Yet, this discovery made by scientists has unearthed a very important fact about mankind…
Modern Humans Are Homo Sapiens
Humans are the largest and most widely distributed primates. All modern humans are classified into the species Homo sapiens — a term first coined by Carl Linnaeus in his 18th-century publication Systema Naturae. The only extant member of H. sapiens emerged around 300,000 years ago.
The Oldest Known Human Ancestors
Australopithecines are thought to be the oldest known human ancestors. Australopithecines are an evolutionary generation of early hominins that were all bipedal to some degree. Bipeds are species that can walk on two legs. Australopithecine brains were just slightly bigger than that of an ape.
Furthermore, they had adapted to a diet that included at least some difficult-to-chew items on occasion. These distant ancestors of Homo sapiens first appeared in Africa about four million years ago, according to researchers. Then again, they would have looked nothing like we do today.
What Are Hominins?
Hominins are members of the zoological family, Hominini. Out of the Hominini, only one type has survived today — Homo sapiens, also known as human beings. The word “hominin” is most commonly used in reference to extinct members of human ancestry, some of whom are now widely known thanks to fossil evidence.
Upright stance, bipedal mobility, larger brains, and behavioral features like specialized tool use and, in some cases, the ability to communicate through language are characteristics that have separated hominins from other primates, living and extinct.
The Various Species Emerge
According to experts, various Homo species began to arise. They developed longer legs that were more suited to running and walking. Then, their brains started to expand. These modifications may have signaled a shift in behavior when these early humans began to hunt and eat more carnivorous foods.
Then, around 700,000 years ago, the Homo heidelbergensis appeared in Africa and Eurasia. Experts have speculated that these hominins resembled contemporary humans in appearance, establishing the foundation for how their successors would evolve. They also behaved differently than their predecessors.
A Little About the Homo Heidelbergensis
Homo heidelbergensis is an extinct archaic human species discovered in Africa, Europe, and probably Asia from 600,000 to 200,000 years ago. The word was originally used in literature in 1908 to refer to an ancient human jaw discovered in 1907 near Mauer, Germany — less than 10 miles southeast of Heidelberg.
Several extinct mammals from around 500,000 years ago were discovered among the fossils discovered with the Heidelberg jaw. The Heidelberg jaw, also known as the Mauer jaw, is extremely broad and chinless.
What Happened to Homo Heidelbergensis?
Homo heidelbergensis was reportedly more clever than those that came before. Members, for instance, used sophisticated tools — not to mention that they perfected their hunting skills. Some speculate that people may have banded together to bring down larger creatures, implying a degree of social unity.
Despite its numerous advantages, Homo heidelbergensis became extinct. Homo heidelbergensis began to develop geographical distinctions, resulting in two distinct human species. Homo heidelbergensis species in Europe developed into Homo neanderthalensis (the Neanderthals), whereas Homo heidelbergensis populations in Africa grew into our own species, Homo sapiens.
The Homo Sapiens and the Homo Heidelbergensis
The number of chromosomes in human ancestors is assumed to have been the same. This allowed for interbreeding between the various species. Experts believe that shortly after moving from Africa and expanding over the world, Homo sapiens began reproducing with Homo neanderthals.
So, roughly 2% of human populations in Asia and Europe have Neanderthal DNA. However, it wasn’t merely Homo sapiens who mated with Homo neanderthals. Members of the species coupled with members of another section of the human family tree, according to studies.
In the sphere of evolutionary sciences, the Denisovans are a relatively recent discovery. In reality, definitive proof of their existence was finally discovered in the 21st century. In 2010, a group of scientists from the Max Planck Institute released the findings of their most recent study.
They discovered evidence of a new type of ancient human after analyzing a molar and a finger bone discovered in the Altai Mountains of Siberia. The species was given the name Denisova after the cave where the specimens were discovered.
Who Are the Denisovans?
The Denisovans, also known as Denisova hominins, were an extinct archaic human race that lived in Asia during the Lower and Middle Paleolithic periods. Denisovans are only identified from a few remnants, thus DNA evidence accounts for the majority of what we know about them.
In the absence of more comprehensive fossil evidence, no official species name has been established. The Denisovans are long-extinct human relatives who shared ancestry with Neanderthals. A closer examination of Denisovan genomes reveals that populations formerly traveled as far as Southeast Asia.
It All Began in a Cave
A tiny bit of bone was discovered by researchers in a cave in Siberia. Initially, the team had no idea that this came from a hominin, which is a phrase that simply referred to all species that are considered human. However, a remarkable story eventually began to unravel.
Denisova Cave is a cave in the Altai Mountains’ Bashelaksky Range in Siberia, Russia. Paleoarchaeological and paleontological finds have been found in the cave. The cave contains Denisova hominin bone pieces, including artifacts dated to around 40,000 B.P.
What Did the Bone Signify?
Despite the fact that the bone had been lost for years, it was eventually discovered by an adventurous researcher. Viviane Slon took the risk of extracting DNA from the artifact as well.
Yet what she discovered has thrown decades of research into disarray. Slon, a paleogeneticist, began investigating the DNA contained within the sample in an attempt to discover more about this mysterious hominid. However, in the end, she discovered far more than anyone had anticipated.
What Did She Find?
At first glance, the bone did not appear to be very noteworthy. It is thought to have come from a teenager who was approximately 13, and it’s only one inch long. Considering that the Denisovans colonized this small part of the Altai Mountains, she’s supposed to have died around 90,000 years ago.
Slon was taken aback when she looked at the DNA in the mitochondria of the bone. This form of the cellular structure comprises a material that a child receives only from their mother.
The Evidence Reveals…
In this example, evidence showed that the adolescent was a descendent from a female Neanderthal. Their understanding of genetics indicates that this material is passed down both male and female lineages, allowing scientists to discover a little more about the ancient teenage girl’s father.
However, the results were so surprising that she thought she had made a mistake at first. Her mother possessed Neanderthal DNA, but her father was a Denisovan mixed with Neanderthal DNA. The paleogeneticist determined the girl’s genetic makeup was surprisingly diverse while studying the bone matter.
Why Is DNA Important?
Scientists can trace the ancient hominin’s paternal lineage since nuclear DNA is inherited from both mother and father. To begin, the paternal lineage closely matched the Denisovan genetic profile. Furthermore, the child’s DNA contained an unusually high level of diversity — a statistic known as heterozygosity.
This can tell experts how closely a person’s mother and father are related. You would have very little heterozygosity if your parents were cousins. On the other hand, heterozygosity would be significant if they were from completely separate hominid species.
What Does This Mean?
Slon had somehow uncovered one of the greatest discoveries of human evolution — a first-generation offspring born of interspecies interbreeding. We knew from earlier research that Neanderthals and Denisovans may have had offspring together on occasion.
It seemed doubtful that scientists would be able to capture it in the process, a person who’s actually a first-generation hybrid. In fact, the revelation was so unexpected that it has prompted queries about how prevalent such interbreeding was in the first place.
The Neanderthals & Denisovans Met Frequently
According to Svante Pääbo from the Max Planck Institute, it’s astonishing that scientists find this Denisovan/Neanderthal child among some of the minority of ancient people whose genomes have been analyzed. It’s possible that Neanderthals and Denisovans didn’t have several opportunities to socialize.
When they did, however, they must have done it more frequently than scientists previously assumed. Researchers are examining various possibilities, including the possibility that the discovery was nothing more than a lucky break. One of them is that the two hominid species regularly interacted — and interbred.
Denny May Not Be the Only One
However, the teenage girl’s bone, named Denny, was not the only piece of evidence that supports this theory. Up until 2018, scientists have only studied the genetics of a tiny variety of historical humans — 23, to be exact. Despite this, at least two individuals in this small sample exhibited indications of interbreeding amongst species.
Then, in 2018, researchers discovered that Denisovans, who vanished some 50,000 years ago, left part of their genes behind in Homo sapiens. Let us look at some examples.
Consider Oase 1
Take, for example, the person known as Oase 1. This Homo sapiens individual, which you can distinguish by the bottom half of his jaw, is thought to have inhabited Earth some 37,000 years back. Considering his obvious arrival on the human family tree, he was discovered to have Neanderthal DNA.
As shown in a 2015 research published in the international Nature, Oase 1’s Neanderthal forefathers lived only four to six generations ago. Scientists reasoned that, if interbreeding amongst species happened only infrequently, finds like this should be rare.
There could be additional reasons why a first-generation hybrid has already shown up in such a small sample size. Caves like the one in the Altai Mountains, in Green’s perspective, could easily have been preferred gathering places for prehistoric humans, introducing sample bias into the analysis.
According to Katerina Harvati-Papatheodorou of the University of Tübingen, such cross-species exchanges could have been crucial to survival. According to the German scholar, human groupings were quite small and subject to dramatic fatality, as she stated to New Scientist.
Information Gathered From a Tooth
It could be something as simple as a tooth that might reveal information about human evolution. Scientists’ questions aren’t answered by the remnant’s appearance. Instead, scientists devised a method for examining the enamel of an 800,000-year-old chomper.
Furthermore, the findings will shed light on the status of a historic meat-eating relative who was only identified in 1994. Researchers have long maintained that chimpanzees are the sole surviving cousins of humans, and also that the different species parted about seven million years ago.
Evolutionary Changes Between Primates & Humans
However, the evolutionary differences between monkeys and humans aren’t always evident. As a result, scientists and academics have spent years delving into the theories of how we humans got from one point to another.
Lucy, a fragmentary skeleton unearthed in Ethiopia that’s considered to be 3.2 million years old, is among the most renowned fossil discoveries of all time. Lucy had long limbs and a chimp-sized brain, however, doctors could establish she wasn’t a primate since she walked on hind limbs.
A New Piece of the Puzzle
Experts discovered a fragmentary skeleton of another one of our predecessors, the Australopithecus, while researching for Lucy. However, in the instance of these more recent changes, all researchers had was a tooth to work with. As a result, yielding productive results would take years of meticulous analysis.
The tooth, on the other hand, had just enough genetic material to assist scientists in learning more about a certain species. So while researching this one dental record, they concluded that the human genealogy needed to be expanded.
More Information Appears During an Excavation
Now, experts have known for quite some time that Neanderthals and their related group, Denisovans, share a common ancestry with modern people. However, the species Homo antecessor was never completely right in its place. In fact, the later species’ fossils were finally discovered in 1994 at an ancient site in Spain.
Homo antecessors lived in Western Europe between 1.2 million and 800,000 years ago, according to estimations. During an excavation in Spain’s Sierra de Atapuerca zone, paleoanthropologists discovered the remains of Homo antecessor.
The Gran Dolina
Paleoanthropologists discovered the Gran Dolina, a large cavern on the location. José Mara Bermudez de Castro, Eudald Carbonell, and Juan Luis Arsuaga made up the team.
Gran Dolina includes 11 separate rock formations in the Earth, the majority of which contain fossilized animal and human remains. Bermudez de Castro, Carbonell, and Arsuaga discovered remnants from the latter type on the sixth layer. Experts dated these to around 780,000 years ago, making them the earliest human remains yet discovered in Europe.
The Homo Antecessors
Homo antecessor was the name given to this species. After all, “homo” means “human,” and “antecessor” implies “early settler,” “pioneer,” and “explorer” in Latin. Given that the relics were Europe’s earliest, the name was appropriate. The Homo antecessors were the very first recognized human population in the region, marking them trailblazers.
The findings also astonished researchers in a variety of ways after additional investigation. The Gran Dolina site revealed details on how Homo antecessors lived back in the day.
Physical Attributes of the Homo Antecessors
The Homo antecessor lacked any morphological characteristics that distinguished itself from other ancient human species. They did, however, have a rare combination of features that set them apart from other ancient individuals, notably in the teeth, cranium, and lower jaw.
In fact, several of their characteristics looked to be more similar to modern humans. Their frame was most likely “similar to present people, but more sturdy,” according to the researchers. Men of this extinct species were generally shorter, ranging in height from 5’2″ to 5’9″.
Other Similarities to Modern Humans
The brain of a Homo antecessor was about 1,000 cubic centimeters in size, compared to a modern typical human brain, which is 1,350 cubic centimeters. Furthermore, the face of the Homo antecessor appeared to be quite recent, particularly in the center of their head.
They also possessed outward-projecting noses and hollowed-out cheekbones, precisely like modern people. While experts are yet to find out more information about what this implies, the facts are interesting. However, the similarities end there, and more ancient-looking traits begin to emerge.
About Their Culture
Excavations at Gran Dolina also turned up approximately 200 stone tools as well as about 300 animal bones, all dated to at least 780,000 years old and found in the same layers as the human remains. Sima del Elefante yielded similar results.
Archaeologists discovered the skeletons of a number of huge creatures, all of which would have arrived at the location in one piece. This suggested that humans did not work as individuals. Instead, they collaborated to stay alive, and they ate together as well.
Brutality of the Homo Antecessors
The bones discovered at Gran Dolina appeared to suggest that Homo antecessors had a harsh side to their character as well. There were cut marks as well as indications of crashing and burning on a few of the species’ bones. This evidence indicates that they were cannibalistic.
Now, cannibalism by the Homo antecessor could have been a drastic step. Other prehistoric species were known to behave in the same way. Cut traces on their unearthed skeletons suggest that Neanderthals engaged in frequent cannibalism and even ritual defleshing of bodies.
What it Meant for Science
As a result, the paleoanthropologists who discovered the Homo antecessor bones performed some preliminary dating. They believed it was the last link between humans and Neanderthals before they separated into their own civilization. The parallels between the bones of Homo antecessor and Neanderthals could not be overlooked.
Now, experts might be able to resolve certain unanswered questions by conducting further research on this issue. They will surely be able to figure out where Homo antecessor fits in the evolutionary tree of mankind.